Take a look at an axial-flux electric motor
In conventional electric motors, the magnetic flux flows radially through an air gap between the rotor and the stator. In an axial-flux motor, the magnetic flux flows parallel to the axle of the motor. The rotor is typically on either side of the stator. Also sometimes known as a pancake rotor, an axial-flux motor can be made much thinner and lighter than other types. In addition, the torque developed is proportional to the diameter of the motor. So more powerful motors grow in diameter rather than in length. The axial-flux motor shown here is from Yasa Motors in the UK. Yasa stands for Yokeless And Segmented Armature. It is basically a brushless dc motor. The unit visible here puts out about 200 kW peak and has a diameter of about 14.5 in. and is a little over 3.5 in. thick. Also visible on the motor are the ports for the oil cooling. Yasa has also made a single-speed transmission for electric vehicles (below) which basically provides dual-reduction gearing for separate torque control of each of two driven wheels. One application is in electric supercars.